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From: Thomas Gleixner <tglx@linutronix.de>
To: syzbot <syzbot+50e25cfa4f917d41749f@syzkaller.appspotmail.com>,
 bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
 linux-kernel@vger.kernel.org, mingo@redhat.com,
 syzkaller-bugs@googlegroups.com, x86@kernel.org, Vlastimil Babka
 <vbabka@suse.cz>, linux-mm@kvack.org
Subject: Re: [syzbot] [kernel?] WARNING in flush_cpu_slab
In-Reply-To: <0000000000008c9d27061915ca9c@google.com>
References: <0000000000008c9d27061915ca9c@google.com>
Date: Thu, 23 May 2024 12:36:20 +0200
Message-ID: <87v834g6hn.ffs@tglx>
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MIME-Version: 1.0
Content-Type: text/plain

CC+: mm folks

On Wed, May 22 2024 at 19:27, syzbot wrote:

> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    2a8120d7b482 Merge tag 's390-6.10-2' of git://git.kernel.o..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17d42b0a980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=5dd4fde1337a9e18
> dashboard link: https://syzkaller.appspot.com/bug?extid=50e25cfa4f917d41749f
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2a8120d7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/78c72ae6bdaf/vmlinux-2a8120d7.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/99dbb805b738/bzImage-2a8120d7.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+50e25cfa4f917d41749f@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> DEBUG_LOCKS_WARN_ON(l->owner)
> WARNING: CPU: 3 PID: 5221 at include/linux/local_lock_internal.h:30 local_lock_acquire include/linux/local_lock_internal.h:30 [inline]
> WARNING: CPU: 3 PID: 5221 at include/linux/local_lock_internal.h:30 flush_slab mm/slub.c:3088 [inline]
> WARNING: CPU: 3 PID: 5221 at include/linux/local_lock_internal.h:30 flush_cpu_slab+0x37f/0x410 mm/slub.c:3146
> Modules linked in:
> CPU: 3 PID: 5221 Comm: kworker/3:3 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> Workqueue: slub_flushwq flush_cpu_slab
> RIP: 0010:local_lock_acquire include/linux/local_lock_internal.h:30 [inline]
> RIP: 0010:flush_slab mm/slub.c:3088 [inline]
> RIP: 0010:flush_cpu_slab+0x37f/0x410 mm/slub.c:3146
> Code: ff e8 e5 b2 fc 08 e9 25 ff ff ff e8 db b2 fc 08 e9 46 ff ff ff 90 48 c7 c6 7f 68 37 8d 48 c7 c7 b6 33 37 8d e8 72 88 6f ff 90 <0f> 0b 90 90 e9 dd fe ff ff 90 48 c7 c6 88 68 37 8d 48 c7 c7 b6 33
> RSP: 0018:ffffc90002b57c98 EFLAGS: 00010086
> RAX: 0000000000000000 RBX: ffffe8ffac1021b0 RCX: ffffffff81510229
> RDX: ffff88801bb7c880 RSI: ffffffff81510236 RDI: 0000000000000001
> RBP: ffff88802790b540 R08: 0000000000000001 R09: 0000000000000000
> R10: 0000000000000000 R11: 000000002d2d2d2d R12: 0000000000000200
> R13: ffffe8ffac1021d0 R14: 0000000000000000 R15: ffffc90002b57d80
> FS:  0000000000000000(0000) GS:ffff88802c300000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000f73ffec2 CR3: 00000000268ca000 CR4: 0000000000350ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
>  process_scheduled_works kernel/workqueue.c:3312 [inline]
>  worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
>  kthread+0x2c1/0x3a0 kernel/kthread.c:389
>  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>  </TASK>
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
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>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
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> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
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>
> If you want to undo deduplication, reply with:
> #syz undup